Pavement.



HERMAN J. RUFLI, OF MOBILE, ALABAMA.

PAVEMENT.

Specification of Letters Patent.

Patented Aug 1a, 1907.

Application filed February 12, 1907. Serial No. 857,029.

' To all whom it may concern:

wearing surface, practically unaffected by heat, cold,

dampness or changing weather conditions.

. It is a purpose of this invention to provide means for maintainingtheelasticity and wearing quality of the surface of the pavement and tothat end, means are provided'for renewing the oil which evaporates,

from the surface of roadways.

It is well known that the surface of a bitumen pavement or any pavementwith wearing surface composed of bitumen oroil for binding agent becomeshard and brittle, owing to the evaporation of the oils containedtherein, and that such hardening of the surface results in the loss ofelasticity and in the disintegration of the particles thereof.

It is furthermore, a purpose of this invention to provide a basic layerof material containing an increased per cent of oil as compared withthat usually employed as a binding agent, such as maltha, or othersimilar oil.

Itis furthermore, the purpose of this invention to provide a top wearingsurface consisting of a mineral base in which a binder is utilized toretain it in a compact mass, to withstand wear and the action of theelements, the said surface layer being renewed, so far as the oil isconcerned, by the absorption of the excess oil in the basic layer.

In the production of a pavement in accordance with this invention, thematerial forming an ordinary country road or city street is excavated asuitable depth and the material thus reclaimed, may be heated to atemperature of 120 to 140 F. for the purpose of drying the same and forthe further purpose of preventing chilling of the binding agent whenapplied. As stated,

for the lower layer I prefer to add to the material thus reclaimed, abinding agent consisting of oil of maltha or any other suitable oil inthe proportion of 20 parts of oil to 80 pzgts reclaimed material. By theterm reclaimed material I mean the material that has and thereafter thetop layer forming the wearing surface of the roadway is placed inposition. The said upper layer is preferably composed ofa portion of thereclaimed material containing the binding agent, consisting of the pitchof coal tar or any other suitable binding agent, and itmay be in theproportion of 85 parts of reclaimed material to 15 parts of the pitch ofcoal tar or any other suitable binding agent, although the proportionmay be varied to 'suit particular requirements. The composition thusproduced is placed in the excavation on the basic layer and suitablyrolled to compress it into a dense mass as is now ordinarily done in thelaying of bitumen or asphaltic pavement. The upper layer will quicklyharden to a suflicient degree to withstand the usual travel, and asevaporation takes place from .the surface of the roadway, by reason ofthe action of the elements, a suitable proportion of oil will be drawnfrom the basic layer (which will act as a reservoir) for renewing thelife of the wearing surface of the roadway.

In carrying out the invention above set forth, it may be desirable toscreen the reclaimed material and utilize the larger pieces or fragmentsfor the base of the pavement, or as a basic layer and employ the finermaterial for the top or the wearing surface, If this method is employed,the larger pieces may be treated with the oil laid, the larger pieces ofthe reclaimed materisl'will I gravitate to the bottom of the mass andform a roadway in which the material is automatically graduated in sizefrom base to surface in much the manner as it would be if put down'insheets or layers of material that is graduated by screening. Inaccomplishing this result, it is necessary to have the material quiteplastic, and to that end a binding agent of less density must beemployed. That is to say, the binding agent must have a greaterproportion of oil than it would have ordinarily and the surface must berolled and re-rolled to cause sufficient agitation of the material tobring about the change in position of the pieces of reclaimed material.Of course, a greater time is required for proper hardening of thesurface, but when the surface becomes solid, the lower portions of thepavement retain its excess of oil and the surface is renewed for aprolonged period. The pavement, therefore, retains its elasticity andwearing quality to anunu sual extent. In mixing the materials 'forproducing this more plastic compound, it is necessary to employapproximately 10% of any suitable oil and 7M1; of coal tar to 83% of thereclaimed material.

I have also found in practice that the principle of this invention maybe employed in connectionwith what is known as wooden pavements made upof blocks,which form the surface of the road-way. Ernploying theinvention in this connection, the. lower layer is formed in practicallythe same manner as that heretofore described containing an excess supplyof oil to the wooden vblocks properly creosoted or otherwise treated arethen placed on the basic layer and the excess oil in the basic layer isabsorbed by the wooden blocks to such an extent that the wooden blocksare preserved for an indefinite period. If desired, a coast of pitchcould be used on the surface of the base and the wooden blocks laiddirectly on the pitch and they would'thereby be held firmly in theirplaces and with the excess of oil used in the base which would overcomeall possibility of the block swelling with the advent of a heavy'rainafter'a protracted dry season. It is well known that the swelling ofwooden blocks after they have been used for several years and the oilhas evaporated, the moisture is allowed to enter with the resultsstated, but by having the excess oil in the basic layer, the oilevaporating from the surface is renewed from the base. The same basicformation will also preserve the life of an asphalt surface or anypavement with a top surface having a binding agent containing oil forregardless of the quality of the oil, a certain percentage willevaporate.

excess supply of oil adapted to feed and replenish the oil evaporatedfrom the upper layer.

2. The herein described method of producing pavement consisting ofexcavating an ordinary roadway to reclaim the material forming saidroadway, drying and heating the said reclaimed material and in replacingthe said material in layers in the excavation with a suitable binder,the lower layer having an excess of oil adapted to replenish the oilevaporated from the upper layer. v

3. The herein described method of producing pavement consisting ofexcavating a roadway to reclaim the material forming said roadway, anddrying the said reclaimed ma terial and adding thereto, a binder havingan excess of oil, the said reclaimed material being replaced in theexcavation and agitated to cause the.heavicr parts to descend andautomatically graduate the size-of the particles from base to top.

4. The herein described method of producing pairenicnt consisting ofexcavating a roadway to reclaim the material forming said roadway, anddrying the said reclaimed mate rial and adding thereto a binder, thesaid reclaimed'material being replaced in the excavation and agitated tocause the heavier parts to descend and automatically graduate the sizeof the particles from base to top.

A pavement consisting of a basic layer having an err cess of oil, andwooden blocks applied to the said basic layer and adapted to have theoil thereof renewed from the basic layer.

In testimony whereof I affix my signature in the pres once of twowitucsses this 8th day of January, 1907.

HERMAN .i. RUFLI.

Witnesses JAMES PETERS, JOHN N. Jones.

